Valves have been conventionally provided with an interlock, normally manually actuated, for permitting the valve operator to be locked in either an open or closed position. However, in fluid systems incorporating a plurality of valves, the interlocks associated with the valves are normally independent of one another, and accordingly exert no control or regulation over the plurality of valves as associated with the complete system.
However, in some fluid systems, proper operation of the system occurs only when the opening and closing of the individual valves is controlled or regulated. For example, some systems will properly operate if only one of the valve assemblies associated with the system is in an open condition, since if several valve assemblies are simultaneously opened, the required fluid quantities and/or pressure will thus not be available within the system. To inusre proper operation in systems of this type, interlocks are known which mechanically interconnect the operators of a plurality of valve assemblies so that only one valve assembly can be operated at a time, with the remaining valve assemblies being mechanically locked in an inoperative condition. While such mechanical interlock systems do provide the necessary control over a plurality of valves, nevertheless these mechanical interlock systems normally require that the valves be grouped together or clustered at a common location in order to facilitate the mechanical interconnection of the interlocks associated with the individual valves. This necessity of having to cluster or group the valves is, however, completely unacceptable and often impossible in many types of fluid systems, particularly when the fluid system is being used to supply a pressure fluid to many remote locations.
While pneumatic interlock systems have also been devised for use in controlling the actuation of valves, nevertheless these known systems have not possessed the simplicity and reliability necessary to provide for precise and dependable control over a plurality of valve assemblies, particularly when said valve assemblies are remotely located with respect to one another.
Accordingly, it is an object of the present invention to provide an improved fluid-actuated interlock system for controlling a plurality of valve assemblies, which interlock system overcomes the above-mentioned disadvantages. More specifically, it is an object of this invention to provide:
1. An interlock system, as aforesaid, which can safely and reliably control the actuation of a plurality of remotely located valve assemblies, which interlock system can regulate the valve assemblies so that only a single valve assembly can be operated at any one time, with the remaining valve assemblies being lockingly held in their inactive positions.
2. An interlock system, as aforesaid, which precisely and reliably regulates the opening and closing of the valve assemblies to thereby provide the system with optimum safety and/or product control.
3. An interlock system, as aforesaid, which is preferably pneumatically actuated whereby individual interlocks can be directly associated with a plurality of remotely located valve assemblies while interconnected in a simple and efficient manner by means of conventional fluid conduits.
4. An interlock system, as aforesaid, which utilizes a simple and reliable fluid switching device and fluid locking device associated with each valve assembly, with the switching and locking devices of the plural valve assemblies being interconnected to a main pressure fluid line and a main manifold, respectively, to thereby simplify the interconnection and operation of the system.
5. An interlock system, as aforesaid, which is of a simple and durable structure, which is economical to manufacture and simple to install, which operates simply and successfully when the valves are remotely located relative to one another, and which insures that only the selected valve assembly will be operated while simultaneously preventing the operation of the remaining valve assemblies.
Other objects and purposes of this invention will be apparent to persons acquainted with systems of this type upon reading the following specification and inspecting the accompanying drawings.